Tilecount binding integration

[tobrun]

With #9906, @asheemmamoowala implemented a seperate util::tileCount() method for computing the number of tiles that need to be downloaded for offline packs.

Sidenote from #9460 (comment):

Note that the tile count depends on the minzoom and maxzoom specified in the source's TileJSON, so calculating it depends on having downloaded at least that resource.

[1ec5]

#11504 tracks the iOS/macOS equivalent to the feature requested here.

[tmpsantos]

tilecount is used in this context for download size estimation.

[LukasPaczos]

Capturing from the #4258, it looks like estimating based only on the tile count would be the least precise of the estimates, we'd have to base it on an average tile size, which might be far off from the actual size of downloaded resources, is that right? If so, is a raw tilecount the way to serve the use-case?

[asheemmamoowala]

@LukasPaczos the tile count is useful for partially determining if the region's size will go over the Offline Tile limit. The actual tiles added to the offline database for a region depends on how many of them are already available in another region. Computing the list of tiles exclusive to a new offline region would require a separate, more expensive computation.